1. Field of the Invention
The present invention relates to a thermowell system for monitoring temperatures in a fixed-bed catalytic reactor, and to a method of constructing such a system. More particularly, the present invention relates to a multi-level thermowell for a fixed-bed reactor, and to a method of assembling the thermowell within the reactor.
2. Description of Prior Art
Fixed-bed catalytic reactors are widely used in hydrocarbon processing and in the chemical process industry. In the operation of these units, it is desirable to measure temperatures at a plurality of spaced locations in the reactor to obtain a temperature profile(s). Temperature measurements are commonly made by moving a thermocouple to various positions within a vertical thermowell, or by positioning multiple thermocouples along the height of the vertical thermowell. Since temperature monitoring throughout the catalyst bed is critical, several vertical thermowells may be installed at specified distances from each other. The number of thermowells will depend on the nature of the catalytic reaction, and on the diameter of the reactor.
Lateral thermowells are also known but will provide a temperature profile in only one plane transverse to fluid flow. Further, lateral thermowells raise mechanical difficulties and expense to install them laterally from the sides of the reactor.
U.S Pat. No. 4,595,300 discloses a system for moving a thermocouple within a vertical thermowell, and U.S. Pat. No. 4,750,357 provides for using multiple thermocouple transverse probes to obtain temperature readings which are in turn used to calculate fluid flow rates.